I must say when I started the manga it was very good but as the plot progresess it goes downhill.
Character.
The character are pretty simple, there is a group that have the main skill to be the mains and important and thats all, all the other are there to die or simple exist. The villain doctor of the pyramid its the most bland villain ever, just being bad because he wants out of knowhere
Art.
The art it really good, great character desing and amazing environment, very detailed. The animals look great to but at certain point they are minimal and forgotten.
Plot
It started with a great mistery that is the whole point of the manga, where are they?, down the road interesting theories are manifested but the big reveal its just bad and rushed. Two of the parents of the kids created the island, why? as memorial. The main group is in the future, how? you will not know. The plot went downhill at aprox the half of the manga, the whole part of the doctor its terrible and so unnecesary. The ending is abrupt, so explanation of the creation of the island and thats it, 3 years later the created a boat and escape end. The villain who tried to kill them? alive and well with them, the bff of the MC somewhere in the island figthing the animals barefist becausehe lost his "limiter" due brain damage so he does no feel pain.
In the end its a manga I don't recommend promises a lot but there is no deliver. Also unnecesary and lost of echi with borderline pedophlia with Mina a child that pretends to be a girl and is sexualised a lot the point its disturbing and not funny.